Te. Kippin et Jg. Pfaus, The development of olfactory conditioned ejaculatory preferences in the male rat I. Nature of the unconditioned stimulus, PHYSL BEHAV, 73(4), 2001, pp. 457-469
We have demonstrated previously that repeated pairing of a neutral odor wit
h copulation produces a subsequent conditioned ejaculatory preference (CEP)
for a female bearing that odor. Here we examine the copulatory components
that comprise the unconditioned stimulus (UCS). In Experiment 1, male Long-
Evans rats were allowed to copulate with scented females for nine sessions
in which they achieved two ejaculations, one ejaculation plus the first in
tromission following the postejaculatory interval (PEI), one ejaculation wi
thout a PEI, or five intromissions without ejaculation. Only the males that
achieved two ejaculations or one ejaculation plus the PEI displayed signif
icant CEP. In Experiment 2, males were allowed to remain in the presence of
the scented female without access to her after different amounts of copula
tory stimulation. Under these conditions, both one and two ejaculations, bu
t not five intromissions, supported the development of CEPs. In Experiment
3, males were allowed to copulate to ejaculation with an unscented female f
ollowed by exposure without access to a scented female. This treatment also
supported the development of CEP. These results indicate that ejaculation
plus a PEI are necessary for the development of CEPs and that the female mu
st be present during the PEI for this to occur. These findings indicate tha
t events during the PEI are the critical components of the UCS for CEP deve
lopment. (C) 2001 Elsevier Science Inc. All rights reserved.